Background:
Incidence of prostate cancer is increasing due to increasing awareness and active PSA screening. High biochemical control (bNED) is achieved with dose escalation by intensity modulated radiotherapy (IMRT) with image guidance, done either by gold marker or pelvic bone matching by KV on-board imaging (OBI) daily before radiation delivery
Aim:
Outcomes of prostate cancer treated by IMRT with image guidance
Methods:
From 2009-2013, 49 non-metastatic adenocarcinoma of prostate of KPS >80, Stage T2b-T4, N0-1 of intermediate and high risk disease were treated by IMRT with image guidance. Three gold markers placed in prostate by transrectal ultrasound. After rectal emptying and bladder filling, a contrast enhanced CT scan of pelvis with 3 mm slice was done. Prostate, seminal vesicles, rectum and bladder were delineated as per EORTC guidelines. The patients were treated with 5-7 beams of 6-MV photon either to whole pelvis RT(50.4Gy/28fr.) followed by prostate boost(26Gy/13fr.) or prostate only radiotherapy (PORT) to a dose of 76Gy/38Fr. Total androgen blockage was used in all
Results:
The median age and PSA was 68 years and 21.6 ng/ml, gleason scores <7- 59%, >7- 41%, stage T2a-2c- 39%, T3-T4- 61%, intermediate risk-25% and high risk-75%, whole pelvis RT+prostate boost-33%, PORT-67%, gold marker matching-64%, bone matching-36%. The median follow up was 29 months. Patients were assessed by DRE and serum PSA. Planning tumour volume received the prescribed doses of 76Gy in 92% cases. Daily image guidance with OBI was mandatory, its compliance was recorded in 50%. Acute and late toxicities recorded as per RTOG criteria. Grade II-III rectal toxicity-10% and grade II bladder toxicity-2% and stricture urethra-4% was observed. Eight patients died (bone/liver metastasis-4, other causes-4). The 4-year bNED was 66%(high risk- 56%) and overall survival was 76%(high risk- 69%)
Conclusions:
The dose escalation in prostate cancer is safe and feasible by IMRT with image guidance